diff --git a/docs/chapter_array_and_linkedlist/array.md b/docs/chapter_array_and_linkedlist/array.md
index 739335938..a2d7627ef 100755
--- a/docs/chapter_array_and_linkedlist/array.md
+++ b/docs/chapter_array_and_linkedlist/array.md
@@ -239,7 +239,7 @@ comments: true
 
     ```dart title="array.dart"
     /* 随机访问元素 */
-    int randomAccess(List nums) {
+    int randomAccess(List<int> nums) {
       // 在区间 [0, nums.length) 中随机抽取一个数字
       int randomIndex = Random().nextInt(nums.length);
       // 获取并返回随机元素
@@ -411,7 +411,7 @@ comments: true
 
     ```dart title="array.dart"
     /* 在数组的索引 index 处插入元素 num */
-    void insert(List nums, int num, int index) {
+    void insert(List<int> nums, int num, int index) {
       // 把索引 index 以及之后的所有元素向后移动一位
       for (var i = nums.length - 1; i > index; i--) {
         nums[i] = nums[i - 1];
@@ -573,7 +573,7 @@ comments: true
 
     ```dart title="array.dart"
     /* 删除索引 index 处元素 */
-    void remove(List nums, int index) {
+    void remove(List<int> nums, int index) {
       // 把索引 index 之后的所有元素向前移动一位
       for (var i = index; i < nums.length - 1; i++) {
         nums[i] = nums[i + 1];
@@ -772,19 +772,19 @@ comments: true
 
     ```dart title="array.dart"
     /* 遍历数组元素 */
-    void traverse(List nums) {
-      var count = 0;
+    void traverse(List<int> nums) {
+      int count = 0;
       // 通过索引遍历数组
       for (var i = 0; i < nums.length; i++) {
         count += nums[i];
       }
       // 直接遍历数组元素
-      for (var num in nums) {
-        count += nums[i];
+      for (int num in nums) {
+        count += num;
       }
       // 通过 forEach 方法遍历数组
-      nums.forEach((element) {
-        count += element;
+      nums.forEach((num) {
+        count += num;
       });
     }
     ```
@@ -954,7 +954,7 @@ comments: true
 
     ```dart title="array.dart"
     /* 在数组中查找指定元素 */
-    int find(List nums, int target) {
+    int find(List<int> nums, int target) {
       for (var i = 0; i < nums.length; i++) {
         if (nums[i] == target) return i;
       }
@@ -1143,7 +1143,7 @@ comments: true
 
     ```dart title="array.dart"
     /* 扩展数组长度 */
-    List extend(List nums, int enlarge) {
+    List<int> extend(List<int> nums, int enlarge) {
       // 初始化一个扩展长度后的数组
       List<int> res = List.filled(nums.length + enlarge, 0);
       // 将原数组中的所有元素复制到新数组
diff --git a/docs/chapter_array_and_linkedlist/linked_list.md b/docs/chapter_array_and_linkedlist/linked_list.md
index cb8a4dd2d..1fba56838 100755
--- a/docs/chapter_array_and_linkedlist/linked_list.md
+++ b/docs/chapter_array_and_linkedlist/linked_list.md
@@ -158,7 +158,7 @@ comments: true
 
     /* 构造函数 */
     ListNode *newListNode(int val) {
-        ListNode *node, *next;
+        ListNode *node;
         node = (ListNode *) malloc(sizeof(ListNode));
         node->val = val;
         node->next = NULL;
@@ -1285,7 +1285,7 @@ comments: true
 
     /* 构造函数 */
     ListNode *newListNode(int val) {
-        ListNode *node, *next;
+        ListNode *node;
         node = (ListNode *) malloc(sizeof(ListNode));
         node->val = val;
         node->next = NULL;
diff --git a/docs/chapter_array_and_linkedlist/list.md b/docs/chapter_array_and_linkedlist/list.md
index 8e2d160cf..5f9b596d9 100755
--- a/docs/chapter_array_and_linkedlist/list.md
+++ b/docs/chapter_array_and_linkedlist/list.md
@@ -1817,13 +1817,13 @@ comments: true
         /* 访问元素 */
         pub fn get(&self, index: usize) -> i32 {
             // 索引如果越界则抛出异常，下同
-            if index < 0 || index >= self.size {panic!("索引越界")};
+            if index >= self.size {panic!("索引越界")};
             return self.arr[index];
         }
 
         /* 更新元素 */
         pub fn set(&mut self, index: usize, num: i32) {
-            if index < 0 || index >= self.size {panic!("索引越界")};
+            if index >= self.size {panic!("索引越界")};
             self.arr[index] = num;
         }
 
@@ -1840,7 +1840,7 @@ comments: true
 
         /* 中间插入元素 */
         pub fn insert(&mut self, index: usize, num: i32) {
-            if index < 0 || index >= self.size() {panic!("索引越界")};
+            if index >= self.size() {panic!("索引越界")};
             // 元素数量超出容量时，触发扩容机制
             if self.size == self.capacity() {
                 self.extend_capacity();
@@ -1856,7 +1856,7 @@ comments: true
 
         /* 删除元素 */
         pub fn remove(&mut self, index: usize) -> i32 {
-            if index < 0 || index >= self.size() {panic!("索引越界")};
+            if index >= self.size() {panic!("索引越界")};
             let num = self.arr[index];
             // 将索引 index 之后的元素都向前移动一位
             for j in (index..self.size - 1) {
diff --git a/docs/chapter_stack_and_queue/stack.md b/docs/chapter_stack_and_queue/stack.md
index 86e7c7d95..77257935c 100755
--- a/docs/chapter_stack_and_queue/stack.md
+++ b/docs/chapter_stack_and_queue/stack.md
@@ -288,7 +288,7 @@ comments: true
     stack.push(4);
 
     /* 访问栈顶元素 */
-    let top = stack[stack.len() - 1];
+    let top = stack.last().unwrap();
 
     /* 元素出栈 */
     let pop = stack.pop().unwrap();
diff --git a/docs/chapter_tree/array_representation_of_tree.md b/docs/chapter_tree/array_representation_of_tree.md
index 534cfefcd..12b78337a 100644
--- a/docs/chapter_tree/array_representation_of_tree.md
+++ b/docs/chapter_tree/array_representation_of_tree.md
@@ -732,7 +732,7 @@ comments: true
 
         /* 获取索引为 i 节点的父节点的索引 */
         parent(i) {
-            return (i - 1) / 2;
+            return Math.floor((i - 1) / 2); // 向下取整
         }
 
         /* 层序遍历 */
@@ -818,7 +818,7 @@ comments: true
 
         /* 获取索引为 i 节点的父节点的索引 */
         parent(i: number): number {
-            return (i - 1) / 2;
+            return Math.floor((i - 1) / 2); // 向下取整
         }
 
         /* 层序遍历 */